Electromagnetic controller



Oct. 19, 1948. A. M. COHEN I 2,451,810

ELECTROMAGNET I C CONTROLLER Filed Dec. 22, 1944 2 Sheets-Sheet 1 INVEN TOR.

Get. 19, 1948. COHEN 1 2,451,819

- ELECTROMAGNETIC CONTROLLER Filed Dec. 22, 1944 2 Sheets-Sheet 2 INVENTOR. Jam 019m C'aMF/Y Patented Oct. 1 9, 1948 ELECTROMAGNETIC CONTROLLER Arthur M. Cohen, New Rochelle, N. Y., assignor to Ward Leonard tion of New York Electric Company, a corpora- Application December 22, 1944, Serial No. 569,369

This invention relates to improved electromagnetic controllers adapted for use as regulators for maintaining constant the voltage, or other variable -factor,-of a dynamo-electric machine.

One object is to provide a compact form of controller which will occupy small space and which is particularly adapted for controlling small units, although it may be utilized for controlling units of large capacity. Another object is to produce an electromagnetic controller of high sensitivity and which is capable of securing close regulation. Another object is to avoidthe objections of a vibrating type of controller and to provide regulation by a series of steps which will insure long life and require little or no attention and avoid objectionable sparking and deterioration of the control contacts. vide an improved form of structure and relationship of the various parts for securing the above mentioned results, various features of which may be utilized for control purposes other than the particular example herein disclosed. Other objects and advantages will be understood from the following description and accompanying drawings which illustrate a preferred embodiment of the invention.

Fig. 1 is a side View; Fig. 2 is a central vertical section taken at right-angles to the plane of Fig. 1 with the prong socket removed; Fig. 3 is a diagram and bottom view of the prong socket shown in Fig. 1; Fig. 4 is a horizontal section on the line 44 of Fig. 2; Fig. 5 is a horizontal section on the line 55 of Fig. 2; and Fig. 6 is a side view of the magnetic plunger element, plunger rod and supporting spider and contact spider. I

Referring to Figs. 1 and 2, the parts are housed in a cylindrical sheet metal casing ID of magnetic material having a removable cylindrical cover H which is adjustable in an axial direction with reference to the casing 10 for a purpose later explained. This is accomplished by providing inclined slots l I a on opposite sides of the cover through which passes screws I lb having a threaded engagement with the upper portion of the casing l 0. It is obvious that by turning the cover or part I I angularly, the cover will be adjusted axially upwardly or downwardly along the casing Ill and is fixed in any desired position by tightening the screws llb. The bottom of the casing is closed by a prong base l2 of the radio tube type and is shown as having eight downwardly projecting prongs I2a, as more particularly shown in Fig. 3. This prong base is notched on its circumierence at four different portions where portions of the lower edge of the casing ID are 5 Claims. (Cl. 200-111) Another object is to procrimped inwardly for retainin the prong base and other parts in fixed position within the casn The eight prongs of the base are adapted to slide into the openings and engage clips or a prong socket l3 of the type customarily used in radio sets. This is shown in Figs. 1 and 3, being composed of two sheets l3a of insulating material fastened together by a pair of rivets I 312 and provided with perforations I at opposite ends for supporting the socket and the regulating unit. As shown in Fig. 3, the prong socket is provided with connecting metal strips H for providing terminal connections between the prongs He and the outside circuit connections. The connectors l4 are provided with portions Ha downwardly extending from the prong socket positioned opposite the openings for receiving the prongs and bent to frictionally engage the prongs when inserted in the socket member. Each portion Ila has extending therefrom a part which passes between the two insulating sheets I3a from which downwardly extend the projections lettered A, B, C, D, E, F, G and H in Fig. 3 for providing connecting terminals to outside devices. The prong base has moulded therewith a downwardly extending central insulated plug I222 having a longitudinally extending key on one side which is adapted to enter a central opening in the prong socket for guiding and correctly positioning the prongs in their engagement with the connectors l4.

Referring to Fig. 2, the magnet coil I5 is shown located within the casing l0 with an intervening cylindrical spacer 15. At the top of the coil is a circular magnetic plate ll having fastened thereto a downwardly projecting cylindrical central portion Ila also of magnetic material. Below the coil is another circular plate I8 of magnetic material, the casing Ill, plate l8 and plate I! with its portion Ila providing the magnetic circuit to and from the plunger of the magnet. The cylindrical plunger 19 has a central opening through which extends the plunger rod 20. This rod is of reduced diameter in its lower portion over which the plunger Hints and impinges against a shoulder on the central portion of the rod. The upper portion of the plunger rod passes freely through the magnetic cylinder 5 la and is formed with a shoulder at its upper portion from which a conical portion 20a of the rod extends upwardly. A narrow spacing ring 21 rests'on the top of the magnet plate I! at its outer portion and above this ring is a second similar ring 22. Between these two rings is secured the rim of a spider 23 of quite thin metal, the face view thereof being shown in Fig. 4. This spider has a central opening through which passes the tapered portion 20a of the plunger rod, the purpose of the spider being to center and yieldably guide the upper end of the plunger rod. As shown in Fig. 4, there extends from the central portion of the spider 23 four radial arms 23a and from one side of the outer end of each arm, a portion 23b extends circumferentially nearly 90; and their ends extend outwardly to unite with the rim 230 of the spider.

The portion which joins the extensions 23b to the rim 23c are each provided with a perforation 23d for the purpose of increasing the flexibility of the interior portion of the spider. The spider is preferably made of steel and tempered to produce a yieldable spring effect, This spider normally tends to hold the plunger rod in its lowest position and serves to slightly oppose the plunger rod in its upward movement and also as a guide therefor. As shown in Fig. 2, the top portion of the cover is indented. A spring 24 of spiral conical form is positioned between the cover and the central portion of the spider 23, the broad base of the spring encircling the indented portion of the cover and the apex of the spring encircling the conical portion 20a of the plunger rod, as shown in Fig. 2. .It is apparent that by loosening the screws l lb and rotating the cover H the tension of the spring 24 may be adjusted as desired to impose a proper downward force on the plunger rod and plunger.

At the lower end of the plunger is positioned another spider 25 of the same. form anclcharacter as the spider 23 already described, the spider 25 being particularly shown in Figs. and 6. Against the lower face of the spider 25 is positioned the contact spider 26. This is formed of thin sheet material preferably of coin silver for obtaining good contact with the respective fixed contacts which are engaged thereby. The spider 26 is formed with a central perforated ring portion from which outwardly extend four radial arms 26a shown 90? apart. From the outer ends of these arms and to one side thereof portions 26b extend in a circumferential direction as shown in Fig. 5. The lower end of the plunger rod passes through the spiders 25 and 26 and through a retaining washer 21, the lower end of the plunger rod being peened over the washer for holding the plunger I 9 and spiders 25 and 26 in fixed position on the plunger rod.

As shown in Fig 2, there is positioned between the insulatin prong base l2 and the spider 26 a circular plate 28 of insulating material. Two pairs of oppositely disposed rivet pins 29 pass through this insulating plate and through the perforations in the spider 25 and through the lower magnetic plate l8 for securing these parts together. A pair of spacing rings 30 similar to the spacing rings 2| and 22 are located on opposite sides of the rim of the spider 25 for positioning the spiders 25 and 26 in the space between the insulating plate 28 and the bottom magnet plate N. The parts are all held in position within the casing in by the crimping of portions of the lower edge of the casing l0 into notches of the prong base l2 and by circumferentially spaced pins 3! fixed to and projecting from the inside of the casing l0 above the spacing ring 22, as shown in Fig. 2.

In-the present instance there are four conducting pins 32 spaced 90 angularly from each other and positioned so that their upper ends come under the ends of the portions 26b. of the contact spider 26 as shown in Fig. 2 and particularly in Fig. 5. These pins are threaded at their upper ends into the insulating plate 28 as shown in Fig.

' 2. The lower ends of the pins are provided with slots 32a so that they may be adjusted by a small screw driver to correctly position the upper contact ends of the pins with reference to the connectors A, C, E and G of Fig. 3. A resistor 33,

preferably in the form of a coiled resistive wire, is connected between the connectors A and C, as shown in Fig. 3; a similar resistor 33m is connected between the connectors C and E; and a similar resistor 33b is connected between the connectors E and G. One terminal of the magnet coil I5 is connected to the prong which engages the connector H and the other terminal thereof is connected to the prong which engages the connector D. A resistor 34 is connected between the connector D and the connector G.

The dynamo-electric machine to be regulated i indicated diagrammatically in Fig. 3 as a direct current generator having an armature 35 and a field winding 36. The load 31 is connected across the outgoing lines of the generator and may be any form of translating device or devices. One terminal of the armature and field winding is connected to the connector H, the remaining a terminal of the field winding being connected to the connector A. The remaining terminal of the armatureisponnected to the connector G. It will be evident that whenthe regulator is inserted in the prong socket and the spider contacts engage all of the upper contact ends of the pins 32, the circuit of the field winding extends from one side of the armature through the field winding to the connector A to its engaging prong, thence through the contact spider to the prong engaging the eonnector G to the other side of the armature. When the plunger is in its uppermost position, the contact spider is out of engagement with all of the pins 32 and all of the field resistances will be included in the field circuit, from one side of the armature through the field winding to the connector A, resistor 33, connector C, resistor 3301., connector E, resistor 33b and connector G to the other side of the armature. The magnet coil [5 is connected across the armature through the coil resistor 34 by a circuit from one side of the armature to the connector H, thence through the magnet coil l5, connector D, resistor 36, connector G and to the other side of the armature. The various resistors indicated in Fig. 3 may be located and housed between the prongs of the base and the extending portions of the connectors, thereby securing a compact form of the apparatus.

In the regulating action, the movement of the magnet plunger between its limiting positions is quite small; and the change of current in the magnet coil required for maintaining the voltage constant is likewise quite small. This results in the magnet having high sensitivity and close regulation of the generator output. The spiders 23 and 25 serve to closely guide the movement of the plun er and plunger rod and are sufllciently yieldable so that they do not materially affect the movement of the plunger as controlled by the 'the voltage of the dynamo-electric machine, or other variable factor, may be set for any desired constant amount.

Regulation is accomplished by control of the field resistors 33, 33aand 33b by including one or more of them in the fieldcircut as conditions may require. When the plunger is in its lowest position, all of these resistors are excluded from the field circuit because they are all short circuited by the contact spider 26; and when the plunger is in its uppermost position all of these resistors are included in the field circuit resulting in a weakened field. 1n the intermediate position of the plunger, one or more of these resistors may be included in the field circuit and this is accomplished in the following manner; The radial arms 01' the contact spider and the extensions therefrom are all in the same plane but the contact ends of the pins 32 are nicely adjusted to lie in different planes; and this difference in adjustment is quite small so that in the range of movement of the plunger and the contact spider, the spider contacts will successively engage the contact heads of the pins 32. Thus the contacting surface of the pin 32 which connects through its prong and socket when the connector G of Fig. 3 is adjusted slightly above the surface of the insulating plate 28; the pin .32 which makes connection with the connector E will have its contact surface ad justed slightly above that connecting with connector G; the pin 32 which connects with the connectorG; willhaVe its contact surface adiusted slightly above that connected with connector E and the pin 32 which is connected with connector A will have its contact surface adjusted slightly above that of the pin connected with connector C.

When no current is supplied to the magnet winding, the plunger is in its lowest position and the contact extensions of the contact spider are flexed so that all of the pins 32 corresponding to the connectors G, E, C and A are engaged thereby, producing an all-out condition of the field resistors in readiness to produce maximum field strength. During starting, the current in the field winding will gradually build up and thereby gradually increase the current in the magnet coil. When the voltage of the generator exceeds the value for which the regulator is adjusted, the magnet plunger will be raised slightly and first raise the spider contact from the pin 32 which is in connection with the connector G and thereby insert the resistor 33b in the circuit of the field winding; and during running conditions whenever the voltage exceeds the desired constant value, the magnet plunger will rise to cause the contact spider to break connection with one or more of the pins 32 and thereby insert one or more of the resistors in the field circuit for reducing the voltage close to its constant value. When the voltage of the generator falls below the desired constant value, the magnet plunger will move slightly downward and thereby short-circuit one or more of the field resistors by the contact spider engaging one .or more of the pins 32. The yieldability of the extensions of the contact spider is so free that they impose a very slight force against the fixed contacts and do not materially affect the position assumed by the plunger as controlled by the current of the magent coil. In view of the fact that the voltage between terminals of the individual field resistors is comparatively small, the arcing at the contacts of the regulator is slight and in view of the fact that the regulator could be given a changes the connections of the field resistors onl when a change of conditions requires it, the parking at the regulator contacts is infrequent. Also. the spider contacts in making and breaking connection with the pins 32 have a slight wiping action. These conditions serve to avoid deterioratlon of the contacts and render them durable over long periods of use compared with the usual type of vibrating contact control.

Instead 01' having contacts 01' the contact spider in the same plane, the extensions of the spider permanent set so as to cause the spider contacts to assume positions in differnt horizontal planes when not in engagement with the fixed contacts and then have the fixed contacts located in the same plane as each other and thereby secure the same regulating efi'ect and control by the movement of the magnetic plunger.

Although a; particular embodiment of the invention has been shown and described, it will be understood that various modifications may be made for adaptation to particular requirements and that various features of construction may be embodied in other forms and types of controllers for various uses without departing from the scope of the invention.

I claim:

1. An electromagnetic controller comprising a cylindrical outside casing, a winding within the casing, a plunger'rodextending axially within the winding, a magnetic plunger carried by said rod at its lower and, contact 'means secured to the lower end of said plunger and rod and having a common conducting portion and a plurality of yieldable contact portions extending therefrom angularly disposed about the axis of the magnet, a base of insulating material fixed within and eX- tendin across the lower end of the casing, and a plurality of contact elements supported by and extending upwardly through said base and having their inner ends positioned opposite said contact portions respectively within the base and positioned relatively to said contact portions to be successively engaged by'said contact portions by the downward movement of the plunger and successively disengaged by the upward movement of the plunger.

2. An electromagnetic controller comprising a cylindrical outside casing, a winding within the casing, 21. plunger rod extending axially within the winding, a magnetic plunger carried by said rod at its lower end, contact means secured to the lower end of said plunger and rod and having a common conducting portion and a plurality of yieldable contact portions extending therefrom angularly disposed about the axis of the magnet, a base of insulating material fixed within and extending across the lower end of the casing, and a plurality of contact elements supported by and extending upwardly through said base and having their inner ends positioned opposite said contact portions respectively within the base and positioned relatively to said contact portions to be successively engaged by said contact portions by the downward movement of the plunger and successively disengaged by the upward movement of the plunger, said contact elements having a threaded engagement with said base and being individually adjustable towards and from said contact portions.

3. An electromagnetic controller comprising a cylindrical outside casing, a, winding within the casing, a plunger rod extending axially within the winding, a magnetic plunger carried by said rod at its lower end, contact means secured to the lower end of said plunger and rod and having a common conducting portion and a plurality of yieldable contact portions-extending therefrom angularly disposed about the axis of the magn t, a base of insulating material fixed within and extending across the lower end or the casing, a plurality of contact elements supported by and extending upwardly through said base and having their inner ends positioned opposite said contact portions respectively within the base and positioned relatively to said contact portions to be successively engaged by said contact portions by the downward movement of the plunger and successively disengaged by the upward movement of the plunger, a cap covering the top of the casing adjustable toward and from the winding; and a spring between the inner side of said cap and the upper end of said plunger rod.

4. An electromagnetic controller comprising a. cylindrical outside casing, a winding within the casing, a plunger rod extending axially within the winding, a magnetic plunger carried by said rod at its lower end, contact means secured to the lower end of said plunger-and rod and having a common conducting portion and a plurality of yieldable contact portions extending therefrom angularly disposed about the axis of the magnet, a base of insulating material fixed within and extending across the lower end of the casing, a

' plurality of contact elements supported by and extending upwardly through said base and having their inner ends positioned opposite said contact portions respectively within the base and positioned relatively to said contact portions to be successively engaged by said contact portions by the downward movement'of the plunger and successively disengaged by the upward movement of the plunger, and yieldable means at opposite ends respectively of said rod and plunger for guiding their movement, each of said yieldable means comprising a fixed outer circular portion magnetic element within the winding, a plurality of movable contacts opposite one end of the winding carried by said magnetic element, a plate of insulating material secured within the casing opposite said movable contacts, a plurality of fixed contact pins supported by said plate and ositioned opposite said movable contacts respectively and individually adjustable in said plate towards and from said movable contacts by threaded engagement with said plate and extending outwardly from said plate and having their inner ends positioned to be successively engaged and successively disengaged during opposite movements respectively of said magnetic element, a base of insulating material secured to the casing opposite and outside said plate, and hollow contact prongs extending outwardly from said base for making external connections, said contact pins extending within and having electrical connection with said prongs respectively.

ARTHUR M. COHEN.

REFERENCES CITED The following references are of record in the 6 file of this patent:

and inwardly extending yieldable supporting por- UNITED STATES PATENTS Number Name Date "730,567 Plassman June 9, 1903 835,493 Baldwin 1 Nov. 13, 1906 1,084,657- Nash Jan. 20, 1914 1,199,046 Bliss Sept. 26, 1916 1,595,893 Terhorst Aug. 10, 1926 1,709,393 Fitch Apr. 16, 1929 1,765,381 Menzel June 24, 1930 1,804,086 Brodt May 5, 1931 1,932,164 Petit Oct. 24, 1933 1,936,535 Albertson Nov. 21, 1933 2,049,310 Nulsen et a1 July 28, 1936 2,064,621 McNairy Dec. 15, 1936 2,116,990 Watanabe May 10, 1938 2,185,683 Barrett et al'. Jan. 2, 1940 2,275,115- Trambetta Mar. 3, 1942 2,335,283 Johnson Nov. 30, 1943 Wellman July 3, 1945 

